JP5075261B2 - Nucleotide-containing tea extract and method for producing the same - Google Patents

Description

  The present invention relates to a method for producing an enzyme-treated tea extract treated with 5'-phosphodiesterase and 5'-adenylate deaminase, an enzyme-treated tea extract obtained by the production method, and an umami enhancing and bitter / astringent taste reducing agent.

  In recent years, due to changes in the drinking form of tea, consumption of packaged tea beverages and powdered tea beverages filled in containers such as cans and PET bottles has increased, and many tea beverages have been developed accordingly. In the development of these tea beverages, various production methods have been examined in order to reproduce the umami and richness of a teapot.

  Among various tea beverages, green tea, in particular, has a strong tendency to be sought after by consumers. The use of seasonings and food additives that require labeling on products is demanded by consumers today. It doesn't meet the needs. Accordingly, methods for improving the taste have been developed, such as a method of performing an enzyme treatment in a tea beverage production process, a method of producing an enzyme-treated tea extract, and adding this tea extract to a tea beverage.

  As a method of performing an enzyme treatment in the production process of tea beverage, for example, tea leaves are enzymatically extracted by combining plant tissue disrupting enzymes such as cellulase and pectinase, and a tea extract having little bitterness and taste and rich taste A method for producing (Patent Document 1), a method for producing an extract with strong umami and richness by treating with protease and tannase (Patent Documents 2 and 3), and an extract containing a large amount of umami components extracted at low temperature In addition, a method (Patent Document 4) is disclosed in which an extraction residue containing a lot of amino acids obtained by treating an extraction residue with a combination of protease and pectinase is mixed to obtain a new flavored tea extract. Moreover, as a method of enzyme-treating the tea extract, there is a method of enhancing the umami taste by converting the theanine contained in the tea extract into glutamic acid by causing glutaminase to act on the tea extract (Patent Documents 5 and 6). It is disclosed. Furthermore, a method (Patent Document 7) is disclosed in which raw tea leaves are treated with various enzymes to produce a tea extract with strong sweetness and umami and a strong green aroma. Although this method aims at strengthening the fragrance, an increasing effect of umami has been reported as a secondary effect.

However, these methods require a long time for the treatment, so that not only the production efficiency is low, but also the possibility of contamination by microorganisms and a decrease in flavor during production is not practical. Furthermore, in these methods, although the umami is strengthened, the balance of the taste as a tea is lost, and it becomes different from the original flavor of tea.

JP 2003-210110 A JP 2003-144049 A JP 2006-61125 A WO2009 / 041555 JP 2005-124500 A JP 2006-42625 A WO2008 / 001848 publication

As described above, various enzyme treatment methods for improving the flavor of tea beverages and tea extracts are known, but the flavor of the enzyme-treated tea extract obtained by these methods is not necessarily satisfactory. However, there has been a demand for the development of tea beverages and tea extracts that can enhance the umami and reduce bitterness and astringency while maintaining the original taste balance of tea.
Therefore, an object of the present invention is to provide a method for producing an enzyme-treated tea extract with enhanced umami and reduced bitterness. It is another object of the present invention to provide an enzyme-treated tea extract with high palatability that enhances the original umami of tea and reduces bitterness and astringency.

  As a result of intensive studies to achieve the above object, the present inventors have found that an extract obtained by extracting tea with water or an aqueous solution contains an enzyme having 5′-phosphodiesterase activity or an enzyme having 5′-phosphodiesterase activity and 5 By working with an enzyme having '-adenylate deaminase activity, the umami of the obtained tea extract is greatly enhanced, and the bitter and astringent taste of the tea extract is also found, and the present invention is completed. It came to.

That is, the method for producing an enzyme-treated tea extract having excellent umami taste and reduced bitterness according to the present invention provides an extract obtained by extracting tea as a raw material with water or an aqueous solution as described in claim 1. A step of allowing an enzyme having 5′-phosphodiesterase activity to act, and the content of guanosine-5′-monophosphate (5′-GMP) in the solid content of the tea extract obtained is 0.1% by weight or more It is the manufacturing method of the enzyme-treated tea extract characterized by these.
In addition, the method for producing an enzyme-treated tea extract having excellent umami taste and reduced bitterness according to the present invention provides an extract obtained by extracting tea as a raw material with water or an aqueous solution as described in claim 2. 5'-GMP and inosine-5'-monophosphate in the solid content of the tea extract having a step of allowing an enzyme having 5'-phosphodiesterase activity and an enzyme having 5'-adenylate deaminase activity to act The total content of (5′-IMP) is 0.1% by weight or more, and is a method for producing an enzyme-treated tea extract.
Furthermore, the present invention according to claim 3 is an enzyme-treated tea extract obtained by the production method according to claim 1 or 2.
The enzyme-treated tea extract according to claim 4 is obtained by adding an enzyme-untreated tea extract to the enzyme-treated tea extract obtained by the production method according to claim 1 or 2. The enzyme-untreated tea extract is a tea extract that does not act on an enzyme having 5′-phosphodiesterase activity or an enzyme having 5′-phosphodiesterase activity and an enzyme having 5′-adenylate deaminase activity.
The umami enhancing and bitter / astringent taste reducing agent according to claim 5 is characterized in that the enzyme-treated tea extract according to claim 3 or 4 is used as an active ingredient.
The umami enhancement and bitter / astringency reduction method according to claim 6 is characterized in that the enzyme-treated tea extract according to claim 3 or 4 is added to a food or drink.

  According to the present invention, an extract obtained by extracting tea with water or an aqueous solution contains an enzyme having 5′-phosphodiesterase activity, an enzyme having 5′-phosphodiesterase activity, and an enzyme having 5′-adenylate deaminase activity. Can be used to produce a well-balanced, high-quality enzyme-treated tea extract with excellent umami and reduced astringency, and this enzyme-treated tea extract can be used to produce tea beverages. By adding to the tea beverage, it is possible to provide a tea beverage that has umami and has reduced bitterness and astringency.

Extraction solution pH and 5'-GMP content in tea extract solids (%) Enzyme reaction temperature and 5'-GMP content in tea extract solids (%) Enzymatic reaction pH and 5'-GMP content (%) in tea extract solids The amount of 5'-phosphodiesterase used relative to 100 mg of tea extract solids and the content of 5'-GMP in the tea extract solids (%) Enzyme reaction time and 5'-GMP content in tea extract solids (%) Extracted solution pH and total content (%) of 5'-GMP and 5'-IMP in tea extracted solids Enzyme reaction temperature and total content of 5'-GMP and 5'-IMP in tea extracted solids (%) Enzymatic reaction pH and total content (%) of 5'-GMP and 5'-IMP in tea extracted solids Enzyme reaction time and total content of 5'-GMP and 5'-IMP in tea extracted solids (%)

Hereinafter, the present invention will be described in detail.
The starting material tea in the method for producing an enzyme-treated tea extract of the present invention refers to a tea tree ( Camellia sinensis ) leaf, an unprocessed extract of a stem, or a processed product produced using these as raw materials. In the case of an unprocessed plucked product, it is preferable that a heat-treated step such as steaming or cooking in a kettle is performed before obtaining the extract. Examples of processed products include non-fermented teas such as green tea and tea flowers, semi-fermented teas such as oolong tea, fully fermented teas such as black tea, and post-fermented teas such as puer tea, all of which are treated with the enzyme according to the present invention. It can be used as a raw material for producing a tea extract. Moreover, in order to raise extraction efficiency, you may grind | pulverize, fracture | rupture, and shred these beforehand. Furthermore, you may use the residue (tea shell) after extracting the said tea as raw material tea. Moreover, you may use commercially available instant powder tea as raw material tea.

As a general example of the extraction process from tea leaves, the raw tea is extracted using 5 to 50 times the amount of water at 20 to 95 ° C. for 5 to 120 minutes while stirring as necessary. The temperature of the water for extracting the tea leaves is preferably about 50 to 100 ° C, more preferably 80 to 95 ° C in terms of extraction efficiency and the like. The pH of the water or aqueous solution used for extraction is not particularly limited, but is preferably in the range of pH 5 to 13, more preferably 5.5 to 12.5, still more preferably 6 to 12, and most preferably 6.5. ~ 11. If extraction is performed at a pH within these ranges, an enzyme-treated tea extract having a stronger taste can be obtained. For adjusting the pH, it is preferable to use sodium bicarbonate (sodium hydrogen carbonate), potassium carbonate or sodium hydroxide, which can be used for food processing. Furthermore, when extracting tea leaves, it is preferable to add an antioxidant such as ascorbic acid, erythorbic acid or their metal salts at the same time to prevent browning of the extract. In addition, the extraction method in the case of using tea leaf residue (tea husk) after tea extraction as the raw material is the same as the above extraction example from tea leaves, but the extraction temperature is preferably 70 ° C or higher, more preferably 85 ° C to 95 ° C. preferable. The pH of water or an aqueous solution used for extraction is preferably alkaline (pH 8.0 to 11). As above, it is preferable to use sodium bicarbonate, potassium carbonate or sodium hydroxide as the pH adjuster.

As an extraction device, it is only necessary that the raw tea and water or an aqueous solution can be kept in contact with each other, and a column method, a batch method, or the like can be adopted. In the column system, an extract can be obtained by passing water or an aqueous solution through a column charged with raw materials. In the batch method, an extraction liquid can be obtained by putting water or an aqueous solution and a raw material into an extraction apparatus such as a kneader or an extraction tank and holding it for a certain period of time. After extraction, the tea husk and the extract are separated into solid and liquid by a filter or centrifugal separation. In this case, the tea husk and the extract may be pressed to increase the extraction efficiency. The pH of the tea leaf extract thus obtained is adjusted to pH 4-7, preferably 4.5-6.5, more preferably 5-6, using an acid (hydrochloric acid, etc.) that can be used for food processing. Adjustment is preferable in that the component change of the extract can be minimized and the enzyme treatment is performed.

  In the present invention, 5'-phosphodiesterase treatment is performed on the extract obtained from the raw tea as described above. If necessary, the extract may be concentrated or dried and then redissolved with water and treated with 5'-phosphodiesterase. The enzyme reaction is not particularly limited as long as the target enzyme-treated tea extract can be produced, but when 5′-phosphodiesterase is allowed to act, for example, the pH is preferably 4 to 6, more preferably 4.5 to 5.5. preferable. The temperature of the enzyme reaction is preferably 25 to 80 ° C, more preferably 35 to 70 ° C. Regardless of the concentration of tea extracted solids during the reaction, the amount of 5'-phosphodiesterase with respect to 100 mg of tea extracted solids is 0.7 to 70 units, more preferably 3.5 to 35 units. As for the enzyme reaction time, for example, when the pH is 5, the reaction temperature is 50 ° C., and the amount of 5′-phosphodiesterase with respect to 100 mg of tea extracted solid content is 7 units, the target enzyme-treated tea extract can be obtained by treating for 15 minutes or more. From the problem of quality deterioration, it is preferably 90 minutes or less, more preferably 60 minutes or less.

When two kinds of enzymes, 5′-phosphodiesterase and 5′-adenylate deaminase, are simultaneously applied to the extract obtained from the raw tea, for example, the pH is preferably 4-6, and 4.5-5 .5 is preferred. The temperature of the enzyme reaction is preferably 25 to 65 ° C, more preferably 35 to 60 ° C.
When 5′-phosphodiesterase is allowed to act and then 5′-adenylate deaminase is allowed to act, the pH when 5′-phosphodiesterase is allowed to act is preferably 4 to 6, more preferably 4.5 to 5.5. . The temperature of the enzyme reaction is preferably 25 to 80 ° C, more preferably 35 to 70 ° C. Next, the pH when 5′-adenylate deaminase is allowed to act is preferably 4 to 6, and more preferably 4.5 to 5.5. The temperature of the enzyme reaction is preferably 25 to 60 ° C, more preferably 35 to 50 ° C. Regardless of the concentration of tea extracted solids during the reaction, the amount of 5'-phosphodiesterase with respect to 100 mg of tea extracted solids is 0.7 to 70 units, more preferably 3.5 to 35 units. The amount of 5′-adenylate deaminase is 25,000 to 500,000 units, more preferably 50,000 to 250,000 units per 100 mg of tea extracted solids.
The enzyme reaction time is preferably 15 minutes or more, for example, when the pH is 5, the reaction temperature is 50 ° C., the 5′-phosphodiesterase amount is 7 units, and the 5′-adenylate deaminase amount is 50000 units. 60 minutes or less is more preferable.

The 5′-phosphodiesterase used in the present invention means 5′-exonuclease [5′-nucleotide phosphodiesterase] (EC 3.1.4.1), and this enzyme has a 3′-OH group. An enzyme that releases 5′-nucleotides sequentially from the 3′-end of oligonucleotides and nucleic acids (RNA and DNA). The origin is not particularly limited, and a commercially available enzyme preparation containing the present enzyme is sufficient. Examples of commercially available enzyme preparations include nuclease “Amano” G sold by Amano Enzyme Inc. In addition, 1 unit of 5′-phosphodiesterase refers to 1 μmol of 1 μm per minute by allowing the enzyme to act on a substrate, adenosine-3′-monophosphate (3′-AMP), under conditions of pH 5.0 and 70 ° C. The amount of enzyme that liberates phosphoric acid.

The 5′-adenylate deaminase used in the present invention means the generic name AMP deaminase (EC 3.5.4.6), which converts 5′-adenylate to 5′-inosinic acid. Enzyme activity to The origin is not particularly limited, and a commercially available enzyme preparation containing this enzyme is sufficient. Examples of commercially available enzyme preparations include deamizyme G sold by Amano Enzyme Co., Ltd. In addition, 10 units of 5′-adenylate deaminase means that the enzyme is allowed to act on a substrate for adenosine-5′-monophosphate (5′-AMP) for 60 minutes under conditions of pH 5.6 and 37 ° C. This is the amount of enzyme when the difference in absorbance at 265 nm, which has the largest difference in absorption wavelength, decreases by 0.001 when 5′-IMP is produced by the action of.

  Furthermore, in order to remove the astringency of the obtained enzyme-treated tea extract, the tea polyphenol in the tea extract can be removed with a synthetic adsorbent, activated carbon, polyvinyl polypyrrolidone (PVPP) or the like. As the synthetic adsorbent used in the present invention, the matrix is styrene, such as XAD-16 (manufactured by Organo Corporation), styrene divinylbenzene, such as Diaion HP-20 (Mitsubishi Chemical Corporation), acrylic, For example, Diaion WK-20 (Mitsubishi Chemical Co., Ltd.), methacrylic, for example Diaion HP-2MG (Mitsubishi Chemical Co., Ltd.), acrylic ester type, for example Amberlite XAD-7 (Organo Co., Ltd.), amide A system such as Amberlite XAD-11 (manufactured by Organo Corporation) or a dextran system such as Sephadex LH-20 (manufactured by Pharmacia Co., Ltd.) can be used. In addition, a column method or a batch method can be adopted as a treatment method using a synthetic adsorbent or activated carbon in the present invention. In the column system, an object can be achieved by feeding an enzyme-treated tea extract or an enzyme-treated tea extract dissolved in water at a constant flow rate to a column filled with a synthetic adsorbent or activated carbon. In the batch method, there is a method in which a synthetic adsorbent, activated carbon, or PVPP is added to an extract and the synthetic adsorbent is separated after stirring for a certain time. However, there is no limitation on the method, and any method may be used as long as the object can be achieved.

The form of the final product in the method for producing an enzyme-treated tea extract of the present invention is not limited and may be liquid, dried solid, or powder. In the case of drying, a generally used method may be used, and examples thereof include a spray drying method (spray drying) and a freeze drying method. As an example, it can be obtained by concentrating the obtained tea extract to Brix (solid content) of 10 to 30% and then freeze-drying or spray-drying.

The enzyme-treated tea extract of the present invention comprises an enzyme-treated tea extract prepared by reacting an enzyme having 5′-phosphodiesterase activity or two kinds of enzymes, 5′-phosphodiesterase and 5′-adenylate deaminase, Also included is a mixture of these separately prepared common tea extracts not subjected to enzyme treatment.
Here, in general tea extracts, as commercial products, for example, the trade name “Polyphenone” of Mitsui Norin Co., Ltd., the trade name “Theafranc” of ITO EN Co., Ltd., and the trade name of Taiyo Kagaku Co., Ltd. “ “Sanphenon” and the like can also be exemplified.

  The bitter and astringent taste reducing and umami enhancing agent of the present invention can enhance the umami in addition to reducing the bitter and astringent taste without affecting the scent of any conventional food or drink. Examples of beverages to which the bitterness and astringency enhancer of the present invention are added include carbonated beverages, citrus (grapefruit, orange, lemon, etc.) fruit juice beverages, fruit juice soft drinks, citrus fruit juice beverages and granule fruit beverages , Tomatoes, peppers, celery, cucumbers, carrots, potatoes, asparagus and other vegetable-based beverages, soy milk and soy milk beverages, coffee beverages, tea beverages, powdered beverages, concentrated beverages, sports beverages, nutritional beverages, alcoholic beverages, etc. Is mentioned.

  The astringency reduction and umami enhancement method of the present invention is a method for reducing the astringency and enhancing the umami by adding to a conventional food or drink.

  Although there is no restriction | limiting in particular about the compounding quantity to the drink of the tea extract of this invention, It is preferable to set a compounding quantity conveniently by the compounding object. In general, the final product may be added in an amount of 5 mg (5 ppm) or more in 100 mL, but the addition of 10 to 1000 ppm is preferable, and the addition of 25 to 500 ppm is most preferable.

The following examples further illustrate the present invention. However, the present invention is not limited to this.

The content of each component in the tea extract and tea beverage was appropriately dissolved and diluted, then filtered through a 0.45 μm membrane filter (DISMIC-13HP; ADVANTEC), and each was performed by the following method.

((A) Tea polyphenol content measurement method)
The tea polyphenol was measured by the iron tartrate method, using ethyl gallate as the standard solution, and calculated as the amount of ethyl gallate (Reference: “Green Tea Polyphenol” Functional Material Effective Use Technology Series No. 10 ). Weigh 2 mL of sample and 5 mL of iron tartrate standard solution, make 25 mL with phosphate buffer solution, and develop color. Absorbance was measured at 540 nm, and the amount of tea polyphenol was determined from a calibration curve using ethyl gallate.
Preparation of iron tartrate standard reagent: 100 mg of ferrous sulfate heptahydrate and 500 mg of sodium / potassium tartrate (Rochelle salt) are dissolved in water to make 100 mL.
Preparation of phosphate buffer: A 1/15 M disodium hydrogen phosphate solution and a 1/15 M sodium dihydrogen phosphate solution are mixed and adjusted to pH 7.5.

((B) 5′-nucleotide content measurement method)
A commercially available reagent (manufactured by SIGMA) was used for 5′-GMP and 5′-IMP, which are standard samples. The standard sample and the measurement sample were appropriately diluted and volumed with ultrapure water to obtain a standard solution and a sample solution, respectively. The standard sample and the measurement sample were filtered through a 0.45 μm hydrophilic PTFE filter (manufactured by Advantech Co., Ltd., DISMIC-13HP), and then quantified using LC-MS / MS under the following conditions.

(Measurement conditions for 5′-nucleotide content)
Apparatus (HPLC): Agilent Technologies, Inc., 1100 Series, (MS / MS): AB SciX, Inc., 3200Q TRAP)
Column: Mightysil RP-18 GP, 2.0 mmΦ × 250 mm (5 μm) (Kanto Chemical Co., Inc.)
Mobile phase (liquid A): methanol: 10 mM ammonium acetate (pH 4.0) = 1.2: 240, (liquid B): methanol: 10 mM ammonium acetate (pH 4.0) = 100: 1 (volume ratio)
Gradient: (Liquid A) 100% hold for 0-12 minutes, 12-15.2 minutes (Liquid B) linear elution from 0% to 70%, 15.2-21 minutes (Liquid B) Retained at 70%, returned to 100% in 21-21.2 minutes (A solution), equilibrated at 100% from 21.2 to 40 minutes (A solution). Flow rate: 200 μl / min, column temperature: 40 ° C., injection volume 10 μL.
Ionization: ESI Turbospray-negative, detection: Multiple Reaction Monitoring (MRM) mode
Detection: 5′-GMP: m / z = 361.8 / 78.8, 5′-IMP: m / z = 346.9 / 78.8.

(Invention product 1, comparison product 1)
Nuclease-treated tea extract 75 g of commercially available green tea leaves were extracted with 1500 g of ultrapure water at 90 ° C. with stirring for 60 minutes. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. The green tea extract was concentrated with an evaporator and then freeze-dried to obtain a green tea extract (Comparative product 1). 3 g of the obtained green tea extract was dissolved in 300 g of ultrapure water to prepare a 1% solution. After heating this to 50 ° C., nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) 300 mg (70 units with respect to 100 mg of tea solid content) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated tea extract (Invention 1). The results are shown in Table 1.

(Preparation of various tea leaf extracts)
(Comparative products 2-9, invention products 2-5)
The various crude tea leaves shown in Table 1 (No. 1 tea, No. 2 tea, Kabuse tea, deep steamed tea, No. 4 tea, Gyokuro) were extracted by the following method, and then each extract was treated with an enzyme to give tea polyphenol content, 5 ' -The total content of IMP and 5'-GMP was measured.
75 g of various crude tea leaves were extracted with 1500 g of water at 90 ° C. for 60 minutes. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. Next, it was concentrated with an evaporator and freeze-dried to obtain a green tea extract (enzyme-untreated tea extract (comparative products 2-6, 8)). 3 g of the obtained green tea extract was dissolved in 300 g of ultrapure water to prepare a 1% solution. After heating this to 50 ° C., nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) 300 mg (70 units with respect to 100 mg of tea solid content) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and freeze-dried to prepare enzyme-treated green tea extracts (Invention products 2 to 5, Comparative products 7 and 9). Table 1 shows the amounts of tea polyphenol, 5′-GMP, 5′-IMP and (5′-GMP + 5′-IMP) of each preparation.

(Sensory evaluation test 1)
Test Example 1: Comparison of Untreated and Enzyme-treated Products of Various Tea Leaf Extracts Evaluation of umami and bitter and astringent taste according to the following test methods for the enzyme-untreated extract and its enzyme-treated extract shown in Table 1 did.
[Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
Each of the prepared tea extracts was dissolved in ion-exchanged water so that the tea polyphenol concentration was 60 mg / 100 mL, and then Comparative product 1 and Invention product 1, Comparative product 2 and Invention product 2, Comparative product 3 and Invention product 3, The comparison product 4 and invention product 4, comparison product 5 and invention product 5, comparison product 6 and comparison product 7, comparison product 8 and comparison product 9 are used in a two-point comparison method for umami and bitterness (two-point identification) Test), and selected one with strong taste and low bitterness. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The significance level was calculated according to this document using the software attached to "Statistical sensory evaluation method that can be done with Excel" (Nikka Giren Publishing Co., Ltd., 2008). The results are shown in Table 2.

As a result of the sensory evaluation test (Table 2), it was found that the extract treated with 5′-phosphodiesterase had a stronger umami in any tea leaf extract than the untreated product. On the other hand, regarding bitter and astringent taste, a decrease in bitterness and astringent taste can be confirmed with an extract having a content of 5′-GMP in the tea extracted solid content of 0.1% or more. I could not confirm. From this result, it was considered that the tea extract having the effect of enhancing the umami and reducing the bitter and astringent taste contains 0.1% or more of 5′-GMP.

Confirmation of 5'-GMP content (comparative product 10) with enhanced umami compared to comparative product 1 and confirming bitterness and astringent taste reduction
Inventive product 1 described in Example 1 and Comparative product 1 are mixed at a ratio by weight (Inventive product 1: Comparative product 1 = 2: 5), and the 5′-GMP content is 0.07% by weight. A tea extract (Comparative product 10) was prepared.

(Comparative product 11)
The inventive product 1 described in Example 1 and the comparative product 1 are mixed at a ratio by weight (inventive product 1: comparative product 1 = 2: 3), and the 5′-GMP content is 0.09% by weight. A tea extract (Comparative Product 11) was prepared.

(Invention 6)
The inventive product 1 described in Example 1 and the comparative product 1 are mixed at a ratio by weight (inventive product 1: comparative product 1 = 3: 2), and the enzyme treatment with a 5′-GMP content of 0.10 wt% is performed. A tea extract (Invention 6) was prepared.

(Invention 7)
Inventive product 1 described in Example 1 and Comparative product 1 were mixed at a weight ratio (Inventive product 1: Comparative product 1 = 4: 1), and a tea extract having a 5′-GMP content of 0.12% by weight was extracted. A product (Invention Product 7) was prepared.

  The component values of the prepared comparative product 1, invention product 1, comparative products 10, 11 and invention products 6 and 7 are shown in Table 3.

(Sensory evaluation test 2)
Test Example 2: Sensory evaluation of the extract shown in Table 3 [Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
Each prepared tea extract was dissolved in ion-exchanged water so that the concentration of tea polyphenol was 60 mg / 100 mL, respectively, then Comparative Product 1 and Comparative Product 10, Comparative Product 1 and Comparative Product 11, Comparative Product 1 and Invention Product 6, Comparison Each combination of Product 1 and Product 7 was tested for umami and bitterness by a two-point comparison method (two-point identification method), and the stronger one and the lower bitterness taste were selected. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The results are shown in Table 4.

  As a result of the sensory evaluation test (Table 4), all the extracts obtained by mixing the comparative product 1 and the inventive product 1 and adjusting the 5′-GMP content have a stronger umami than the comparative product 1. I understood. On the other hand, regarding bitter astringency, when the 5′-GMP content in the tea extract solids was 0.09% or less, the bitter astringency was not reduced, and when it was 0.10% or more, the bitter astringency was reduced. . From this, it was found that the content of 5'-GMP in the tea extract having strong umami and reduced astringency is required to be 0.10% or more.

(Invention 8)
75 g of commercially available green tea leaves were extracted with 1500 g of a 0.15% aqueous sodium hydrogen carbonate solution (pH 8.3) at 90 ° C. for 60 minutes. After solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. 0.1N hydrochloric acid was added to the extract to adjust the pH to 5.5, and after concentration with an evaporator, lyophilized to obtain a green tea extract. 1 g of the obtained green tea extract was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 100 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (70 units with respect to 100 mg of tea solid content) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated tea extract (Invention 8). The component analysis results of this green tea extract are shown in Table 5 and FIG.

(Invention 9)
Invention 9 was prepared in the same manner as Invention 8, except that the solution during tea leaf extraction was changed to a 0.15% aqueous potassium carbonate solution (pH 11.2). The component analysis results of this green tea extract are shown in Table 5 and FIG.

(Invention 10)
Invention product 10 was prepared in the same manner as Invention product 8, except that the solution during tea leaf extraction was changed to a 0.02 M aqueous sodium hydroxide solution (pH 12.4). The component analysis results of this green tea extract are shown in Table 5 and FIG.

(Comparative product 12)
75 g of commercially available green tea leaves were extracted with 1500 g of 0.02M hydrochloric acid (pH 1.5) at 90 ° C. for 60 minutes. After solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. A saturated aqueous sodium hydrogen carbonate solution was added to the extract to adjust the pH to 5.5, and the solution was concentrated by an evaporator and freeze-dried to obtain a green tea extract. 3 g of the obtained green tea extract was dissolved in 300 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 300 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (70 units with respect to 100 mg of tea solid content) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and freeze-dried to obtain an enzyme-treated tea extract (Comparative product 12). The component analysis results of this green tea extract are shown in Table 5 and FIG.

(Comparative product 13)
Comparative product 13 was prepared in the same manner as comparative product 12, except that the solution at the time of tea leaf extraction was changed to a 0.15% citric acid solution (pH 2.7). The component analysis results of this green tea extract are shown in Table 5 and FIG.

As shown in Table 5, it can be used for food processing and extracted with an aqueous solution in which the pH of the extraction solution is adjusted to alkaline (pH 8.3 to 12.4) using sodium bicarbonate, potassium carbonate, or sodium hydroxide. Then, compared with the case of extracting with water (pH 6.2), an enzyme-treated tea extract having a content of 5′-GMP of 1.9 to 2.5 times higher, stronger umami, and reduced bitterness and astringency. Can be prepared. On the other hand, when extracted with an aqueous solution in which the pH of the extraction solution is adjusted to acidic (pH 1.5 to 2.7) using hydrochloric acid or citric acid, which can be used for food processing, 5 ' -The content of GMP decreased to 1/10 or less, no umami, and bitterness and astringency.

(Sensory evaluation test 3)
Test Example 3: Sensory evaluation of the extract shown in Table 5 [Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
Each of the various tea extracts prepared was dissolved in ion-exchanged water so that the concentration of tea polyphenol was 60 mg / 100 mL, and then Invention 1 and Invention 8, Invention 1 and Invention 9, Invention 1 and Invention 10, and Invention Each combination of Product 1 and Comparative Product 12, Invention Product 1 and Comparative Product 13 was tested for umami and bitterness by a two-point comparison method (two-point identification method), with strong umami and low bitterness Was chosen. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The results are shown in Table 6.

As a result of the sensory evaluation test (Table 6), the inventive products 8 to 10 prepared by making the pH of the tea leaf extraction solution alkaline using sodium bicarbonate, potassium carbonate, or sodium hydroxide that can be used for food processing are the inventive products. Since umami was stronger than 1, and bitterness and astringency were reduced, it was found that alkaline extraction is an effective means. On the other hand, the comparative products 12 and 13 prepared by acidifying the pH of the tea leaf extract solution using hydrochloric acid and citric acid that can be used for food processing had no umami taste, and the bitter and astringent taste was stronger than the inventive product 1. From this, it was found that the target enzyme-treated tea extract cannot be obtained when the pH of the solution during tea leaf extraction is acidic.

Preparation of enzyme-treated tea extract with reduced tea polyphenol content (Invention 11, Comparative 14)
Invention product 10, 2.5 g was dissolved in 250 g of ultrapure water to prepare a 1% solution. This solution was applied to a column packed with Diaion HP-20 (Mitsubishi Chemical Corporation) resin (250 mL) equilibrated with water and eluted with water (750 mL), and the non-adsorbed fraction of Diaion HP-20 was obtained. Obtained. Next, this non-adsorbed fraction was concentrated with an evaporator and then freeze-dried to obtain 1.6 g of an enzyme-treated tea extract (Invention 11) having a reduced content of tea polyphenol. Further, methanol was passed through a Diaion HP-20 column to obtain an adsorbed fraction. The HP-20 adsorption fraction was concentrated with an evaporator and then freeze-dried to obtain 0.9 g of an adsorption fraction (Comparative product 14). The component analysis results of these green tea extracts are shown in Table 7.

  As shown in Table 7, as a result of treating Invention 10 with Diaion HP-20, the enzyme-treated tea extract has a low content of tea polyphenol in the solid content and a 1.5-fold increase in the 5'-GMP content. (Invention 11) was obtained.

Reduction of tea polyphenols by activated carbon (Comparative products 15-19, invention products 12-16)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm, pH 8.2) containing sodium bicarbonate and sodium ascorbate. After solid-liquid separation, the mixture was filtered using a filter paper (No. 28, manufactured by Advantech Co., Ltd.), adjusted to pH 5.0 by adding 0.1N hydrochloric acid to obtain a green tea extract.
(1) 500 mL of the obtained green tea extract is heated to 50 ° C., and then added with nuclease “Amano” G (720 mg (5040 units) manufactured by Amano Enzyme Co., Ltd.), incubated for 30 minutes, and then in boiling water for 3 minutes. The reaction was stopped by heating, and the resulting enzyme reaction solution was subjected to the following treatments (A) to (E).
(A) 100 mL of the enzyme reaction solution was concentrated as it was with an evaporator and then lyophilized to obtain an enzyme-treated tea extract (Invention 12).
(B) 100 mL of the enzyme reaction solution was added with 1.45 g of activated carbon (0.60 times the amount of tea extract solids) and stirred at room temperature for 60 minutes. After removing the activated carbon, it was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated tea extract (Invention 13).
(C) 100 mL of the enzyme reaction solution was treated in the same manner as (B) except that the amount of activated carbon was changed to 2.16 g (0.90 times the amount of tea extract solids). A product (Invention 14) was obtained.
(D) 100 mL of the enzyme reaction solution was treated in the same manner as (B) except that the amount of activated carbon was changed to 2.90 g (1.20 times the amount of tea extract solids), and enzyme-treated tea extraction A product (Invention 15) was obtained.
(E) 100 mL of the enzyme reaction solution was treated in the same manner as (B) except that the amount of activated carbon was changed to 3.63 g (1.51 times the solid content of the tea extract), and the enzyme-treated tea extract was processed. (Invention product 16) was obtained.
(2) 500 mL of the obtained green tea extract was subjected to the following treatments (i) to (v).
(I) 100 mL was concentrated as it was with an evaporator and freeze-dried to obtain a tea extract (Comparative Product 15).
(Ii) 100 mL of green tea extract was added with 1.44 g of activated carbon (0.63 times the solid content of tea extract) and stirred at room temperature for 50 minutes, and then the activated carbon was removed to obtain an activated carbon treatment solution. After heating the obtained activated carbon treatment liquid to 50 ° C., 23.7 mg (166 units) of nuclease “Amano” G (manufactured by Amano Enzyme) was added, incubated for 30 minutes, and then heated in boiling water for 3 minutes. The enzyme reaction was stopped. This was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated tea extract (Comparative Product 16).
(Iii) 100 mL of green tea extract has an activated carbon amount of 2.14 g (0.93 times the solid content of tea extract) and an amount of nuclease “Amano” G (manufactured by Amano Enzyme) to 20.7 mg (145 units). Except having changed, it processed by the method similar to (ii), and obtained the enzyme treatment tea extract (comparative product 17).
(Iv) 100 mL of green tea extract has an activated carbon amount of 2.75 g (1.2 times the amount of tea extract solids) and a nuclease “Amano” G (Amano Enzyme Co., Ltd.) amount of 15.5 mg ( The enzyme-treated tea extract (Comparative product 18) was obtained in the same manner as in (ii) except that it was changed to 109 units).
(V) 100 mL of green tea extract has an activated carbon amount of 3.2 g (1.4 times the amount of tea extract solids) and a nuclease “Amano” G (Amano Enzyme Co., Ltd.) amount of 12.5 mg ( The enzyme-treated tea extract (Comparative product 19) was obtained by the same method as (ii) except that the unit was changed to 88 units). The component analysis results of these green tea extracts are shown in Table 8.

As shown in Table 8, when reducing tea polyphenols by activated carbon treatment in the enzyme-treated tea extract production process, 5% in the solid content of the enzyme-treated tea extract is treated with activated carbon after 5′-phosphodiesterase treatment. It was possible to obtain an enzyme-treated tea extract having a reduced tea polyphenol content while suppressing a decrease in the '-GMP content.

Enzyme reaction temperature (Invention products 17-21)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm) containing sodium bicarbonate and sodium ascorbate. After solid-liquid separation, the mixture was filtered using filter paper (No. 28, manufactured by Advantech Co., Ltd.), adjusted to pH 5.0 by adding 0.1N hydrochloric acid to obtain a green tea extract. The obtained green tea extract was subjected to the following treatments (A) to (E). That is,
(A) After 200 mL was heated to 25 ° C., 200 mg (1400 units) of nuclease “Amano” G (manufactured by Amano Enzyme) was added and reacted for 30 minutes. After the reaction, it was heated in boiling water for 3 minutes to stop the enzyme reaction, concentrated with an evaporator and lyophilized to obtain an enzyme-treated tea extract (Invention 17).
(B) 200 mL of the enzyme-treated tea extract (Invention Product 18) was obtained by performing the same treatment as (A) except that the temperature of the enzyme reaction was changed to 35 ° C.
(C) 200 mL of the enzyme-treated tea extract (Invention 19) was obtained by performing the same treatment except that the temperature of the enzyme reaction was changed to 50 ° C.
(D) 200 mL of the enzyme-treated tea extract (Invention Product 20) was obtained by carrying out the same treatment as (A) except that the temperature of the enzyme reaction was changed to 60 ° C.
(E) 200 mL of the enzyme-treated tea extract (Invention 21) was obtained by performing the same treatment as (A) except that the temperature of the enzyme reaction was changed to 70 ° C. The component analysis results of these green tea extracts are shown in Table 9 and FIG.

  If the enzyme reaction temperature is 25 ° C. or higher as a result of 5′-phosphodiesterase treatment at an enzyme reaction temperature of 25 to 70 ° C. with the enzyme amount, reaction time and enzyme reaction pH being constant for the tea solids, the target enzyme treatment It was found that a tea extract can be obtained.

Enzyme reaction pH
(Comparative products 20, 21, invention products 22-26)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm) containing sodium bicarbonate and sodium ascorbate. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract.
(A) Add 0.1N hydrochloric acid to 200 mL of this green tea extract, adjust to pH 3.0, warm to 50 ° C., and add 200 mg (1400 units) of nuclease “Amano” G (Amano Enzyme Co., Ltd.) The reaction was started. After the reaction for 30 minutes, the enzyme reaction was stopped by heating in boiling water for 3 minutes, concentrated by an evaporator and freeze-dried to obtain an enzyme-treated tea extract (Comparative Product 20).
(B) An enzyme-treated tea extract (Invention 22) was obtained by performing the same treatment as (A) except that the pH of the enzyme reaction was changed to 4.0 (pH adjustment: using 0.1N hydrochloric acid). .
(C) An enzyme-treated tea extract (Invention 23) was obtained by performing the same treatment as (A) except that the pH of the enzyme reaction was changed to 4.5 (pH adjustment: using 0.1N hydrochloric acid). .
(D) An enzyme-treated tea extract (Invention 24) was obtained by performing the same treatment as (A) except that the pH of the enzyme reaction was changed to 5.0 (pH adjustment: using 0.1N hydrochloric acid). .
(E) An enzyme-treated tea extract (Invention 25) was obtained by performing the same treatment as (A) except that the pH of the enzyme reaction was changed to 5.5 (pH adjustment: using 0.1N hydrochloric acid). .
(F) An enzyme-treated tea extract (Invention 26) was obtained by performing the same treatment as in (A) except that the pH of the enzyme reaction was changed to 6.0 (pH adjustment: using sodium bicarbonate).
(G) An enzyme-treated tea extract (Comparative Product 21) was obtained by performing the same treatment as (A) except that the pH of the enzyme reaction was changed to 7.0 (pH adjustment: using sodium bicarbonate). The results of component analysis of these green tea extracts are shown in Table 10 and FIG.

  Table 10 and FIG. 3 show the results of the reaction of 5'-phosphodiesterase with the enzyme amount, the reaction time, and the reaction temperature with respect to the tea solid content being constant and the pH being 3.0 to 7.0. As a result, at pH 3.0 and pH 7.0, the reaction of 5′-phosphodiesterase did not proceed at all, and the target enzyme-treated tea extract could not be obtained, but between pH 4.0 and 6.0. The target enzyme-treated tea extract could be prepared.

Examination of enzyme amount (Invention products 27-32)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm) containing sodium bicarbonate and sodium ascorbate. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. To the obtained green tea extract, 0.1N hydrochloric acid was added to adjust to pH 5.0, concentrated with an evaporator and freeze-dried to obtain a tea extract. After dissolving 21.3 g of the obtained tea extract in 1000 mL of ultrapure water,
(A) After 100 mL of this lysate was heated to 50 ° C., 2.1 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (0.7 units with respect to 100 mg of tea solid content) was added to react. Started. After the reaction for 30 minutes, the enzyme reaction was stopped by heating in boiling water for 3 minutes, concentrated with an evaporator and freeze-dried to obtain an enzyme-treated tea extract (Invention 27).
(B) Enzyme treatment with the same treatment as (A) except that the amount of nuclease “Amano” G (Amano Enzyme Co., Ltd.) was changed to 10.7 mg (3.5 units for 100 mg of tea solids). A tea extract (Invention 28) was obtained.
(C) Enzyme-treated tea extraction using the same treatment as (A) except that the amount of nuclease “Amano” G (Amano Enzyme Co., Ltd.) was changed to 21.3 mg (7 units for 100 mg of tea solids). A product (Invention 29) was obtained.
(D) Enzyme-treated tea extraction using the same treatment as (A) except that the amount of nuclease “Amano” G (Amano Enzyme Co., Ltd.) was changed to 63.9 mg (21 units for 100 mg of tea solids). A product (Invention 30) was obtained.
(E) Enzyme-treated tea extraction using the same treatment as (A) except that the amount of nuclease “Amano” G (Amano Enzyme Co., Ltd.) was changed to 106.5 mg (35 units for 100 mg of tea solids). A product (Invention 31) was obtained.
(F) The enzyme-treated tea extract (A) was treated in the same manner as in (A) except that the amount of nuclease “Amano” G (Amano Enzyme Co., Ltd.) was changed to 213 mg (70 units for 100 mg of tea solids). Inventive product 32) was obtained. The component analysis results of these green tea extracts are shown in Table 11 and FIG.

  Table 11 and FIG. 4 show the results obtained by changing the amount of 5'-phosphodiesterase relative to the tea solid content while keeping the enzyme reaction time, the enzyme reaction pH, and the enzyme reaction temperature constant. As a result, the target enzyme-treated tea extract could be obtained in all test sections in which the amount of 5'-phosphodiesterase with respect to 100 mg of the tea extract solid content was reacted at 0.7 to 70 units.

Examination of enzyme reaction time (Comparative products 22, 23, invention products 33-48)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm) containing sodium bicarbonate and sodium ascorbate. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. 0.1N hydrochloric acid was added to the obtained green tea extract to adjust to pH 5.0. The tea extract was obtained by concentrating with an evaporator and freeze-drying. After dissolving 21.3 g of the obtained tea extract in 1000 mL of ultrapure water,
(A) 300 mL of this lysate was heated to 50 ° C., and then added with nuclease “Amano” G (manufactured by Amano Enzyme) 6.3 mg (0.7 units for 100 mg of tea solids) The reaction was started. Sampling was performed at 0 minutes, 30 minutes, 60 minutes, 90 minutes, 120 minutes, and 150 minutes after the start of the reaction, and the enzyme reaction was stopped by heating in boiling water for 3 minutes. After concentration with an evaporator and freeze-dried, enzyme-treated tea extracts (Comparative products 22, 23 and Invention products 33 to 36) were obtained.
(B) Enzyme-treated tea extraction using the same treatment as (A) except that the amount of nuclease “Amano” G (Amano Enzyme Co., Ltd.) was changed to 63.9 mg (7 units for 100 mg of tea solid content). Products (Inventions 37 to 42) were obtained.
(C) Enzyme-treated tea extraction by the same treatment as (A) except that the amount of nuclease “Amano” G (Amano Enzyme Co., Ltd.) was changed to 191.7 mg (21 units for 100 mg of tea solid content). Products (Inventions 43 to 48) were obtained. The component analysis results of these green tea extracts are shown in Table 12 and FIG.

As shown in Table 12 and FIG. 5, the enzyme treatment time for obtaining the target tea extract varies depending on the amount of enzyme. For example, the amount of 5′-phosphodiesterase with respect to 100 mg of tea extract solids is 0.7 units. If it exists, it should just process for 60 minutes or more, and if it is 7 units or more, the target tea extract can be prepared by processing for 15 minutes or more.

Preparation of oolong tea extract (Comparative product 24, Invention product 49)
75 g of Oolong tea leaves were extracted with 1500 g of water at 90 ° C. for 60 minutes. After solid-liquid separation, filtration was performed using filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain Oolong tea extract. This oolong tea extract was concentrated with an evaporator and then freeze-dried to prepare a oolong tea extract (Comparative Product 24). 1 g of the prepared oolong tea extract (Comparative Product 24) was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 50 mg of nuclease “Amano” G (manufactured by Amano Enzyme) (35 units for 100 mg of tea solid content) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to prepare an enzyme-treated oolong tea extract (Invention 49). The results of component analysis of the comparative product 24 and the invention product 49 are shown in Table 13.

(Comparative product 25, invention product 50)
75 g of Oolong tea leaves were extracted with 1500 g of 0.15% sodium hydrogen carbonate solution (pH 8.3) for 60 minutes. After solid-liquid separation, filtration was performed using filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain Oolong tea extract. 0.1 N hydrochloric acid was added to the oolong tea extract to adjust the pH to 5.0, and then concentrated with an evaporator and freeze-dried to prepare a oolong tea extract (Comparative Product 25). 1 g of the prepared oolong tea extract (Comparative product 25) was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 50 mg of nuclease “Amano” G (manufactured by Amano Enzyme) (35 units for 100 mg of tea solid content) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated oolong tea extract (Invention 50). The results of component analysis of the comparative product 25 and the inventive product 50 are shown in Table 13.

(Sensory evaluation test 4)
Test Example 4: Sensory evaluation of the extract shown in Table 13 [Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
Each prepared tea extract is dissolved in ion-exchanged water so that the concentration of tea polyphenol is 60 mg / 100 mL, and then the combination of Comparative Product 24 and Invention Product 49, and Comparison Product 25 and Invention Product 50 is used for umami and bitterness. The test was conducted by a two-point comparison method (two-point identification method), and a strong taste and a low bitter taste were selected. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The results are shown in Table 14.

  As a result of the sensory evaluation test (Table 14), it was found that the oolong tea extract treated with 5'-phosphodiesterase had enhanced umami and significantly lower bitterness compared to untreated products (Comparative products 24 and 25).

Preparation of black tea extract (Comparative product 26, Invention product 51)
75 g of tea leaves were extracted with 1500 g of water at 90 ° C. for 60 minutes. After solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a black tea extract. This black tea extract was concentrated with an evaporator and then freeze-dried to obtain a black tea extract (Comparative Product 26). 1 g of the prepared black tea extract (Comparative product 26) was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 50 mg of nuclease “Amano” G (manufactured by Amano Enzyme) (35 units for 100 mg of tea solid content) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and freeze-dried to prepare an enzyme-treated black tea extract (Invention 51). The results of component analysis of these tea extracts are shown in Table 15.

(Comparative product 27, invention product 52)
75 g of tea leaves were extracted with 1500 g of a 0.15% sodium hydrogen carbonate solution (pH 8.3) for 60 minutes. After solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a black tea extract. 0.1N hydrochloric acid was added to this black tea extract to adjust to pH 5.0, and after concentration with an evaporator, freeze dried, a black tea extract (Comparative Product 27) was prepared. 1 g of the prepared black tea extract (Comparative Product 27) was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 50 mg of nuclease “Amano” G (manufactured by Amano Enzyme) (35 units for 100 mg of tea solid content) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and freeze-dried to obtain an enzyme-treated black tea extract (Invention 52). The results of component analysis of these tea extracts are shown in Table 15.

(Sensory evaluation test 5)
Test Example 5: Sensory evaluation of the extract shown in Table 15 [Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
Each prepared tea extract was dissolved in ion-exchanged water so that the concentration of tea polyphenol was 60 mg / 100 mL, respectively, and then the combination of Comparative Product 26 and Invention Product 51, Comparative Product 27 and Invention Product 52, and umami and bitter taste. The test was conducted by a two-point comparison method (two-point identification method), and a strong taste and a low bitter taste were selected. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The results are shown in Table 16.

Preparation of tea extract treated with nuclease and deaminase (Comparative product 28, Invention product 53)
75 g of commercially available green tea leaves were extracted with 1500 g of ultrapure water at 90 ° C. with stirring for 60 minutes. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. The green tea extract was concentrated with an evaporator and then freeze-dried to obtain a green tea extract (Comparative product 28). 3 g of the obtained green tea extract (Comparative product 28) was dissolved in 300 g of ultrapure water to prepare a 1% solution. After heating this to 50 ° C., 90 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (21 units for 100 mg of tea solid content) and 90 mg of deamizyme G (manufactured by Amano Enzyme Co., Ltd.) (100 mg of tea solid content) 150,000 units) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated tea extract (Invention 53). The component analysis results of these green tea extracts are shown in Table 17.

(Preparation of various green tea extracts)
(Comparative products 29-34, invention products 54-59)
The various crude tea leaves shown in Table 17 (No. 1 tea, No. 2 tea, Kabuse tea, deep steamed tea, No. 4 tea, Gyokuro) were extracted by the following method, and each extract was subjected to enzyme treatment, followed by polyphenol content, 5'- The total content of IMP and 5′-GMP was measured.
75 g of various crude tea leaves were extracted with 1500 g of water at 90 ° C. for 60 minutes. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. Next, it was concentrated by an evaporator and freeze-dried to obtain various green tea extracts (enzyme-untreated tea extract). 3 g of the obtained green tea extract was dissolved in 300 g of ultrapure water to prepare a 1% solution. After heating to 50 ° C., 300 mg (2100 units) of nuclease “Amano” G (manufactured by Amano Enzyme) and 300 mg (15000000 units) of deamizyme G (manufactured by Amano Enzyme) were added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and freeze-dried to prepare an enzyme-treated green tea extract. Table 17 shows the component analysis results of these 12 kinds of green tea extracts.

(Sensory evaluation test 6)
Test Example 6: Comparison of various green tea extracts with enzyme-untreated products and enzyme-treated products With respect to each enzyme-untreated extract and its enzyme-treated extract shown in Table 17, the umami and bitter taste were determined according to the following test methods. evaluated.
[Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
The prepared various tea extracts were dissolved in ion-exchanged water so that the concentration of tea polyphenol was 60 mg / 100 mL, respectively, and then comparative product 28 and invention product 53, comparison product 29 and invention product 54, comparison product 30 and invention product 55, comparison A combination of product 31 and invention 56, comparison product 32 and invention product 57, comparison product 33 and invention product 58, comparison product 34 and invention product 59, and a two-point comparison method (two-point identification method) ), And selected one with strong taste and low bitterness. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The results are shown in Table 18.

As a result of the sensory evaluation test (Table 18), the extract treated with 5′-phosphodiesterase (nuclease) and 5′-adenylate deaminase (deaminase) has an umami taste in any green tea extract compared to the untreated enzyme. It was found that bitterness and astringency were reduced. In these enzyme-treated green tea extracts, it was found that the extract (Invention 58, Invention 59) having a 5′-GMP content of less than 0.10% has strong umami and reduced bitterness. . And in these extracts, since the total content of 5′-GMP and 5′-IMP was 0.10% or more, the total of 5′-GMP and 5′-IMP was 0.1% or more. The green tea extract was considered to be able to exert the above two effects.

(Comparative product 35)
The inventive product 53 described in Example 12 and the comparative product 28 were mixed in a weight ratio (inventive product 1: comparative product 5 = 2: 5), and the total content of 5′-GMP and 5′-IMP was 0.08. A weight% enzyme-treated tea extract (Comparative Product 35) was prepared.

(Invention 60)
The inventive product 53 described in Example 12 and the comparative product 28 were mixed at a weight ratio (inventive product 1: comparative product 5 = 2: 3), and the total content of 5′-GMP and 5′-IMP was 0.00. A 10% by weight enzyme-treated tea extract (Invention 60) was prepared.

(Invention 61)
The inventive product 53 described in Example 12 and the comparative product 28 were mixed at a weight ratio (inventive product 1: comparative product 5 = 3: 2), and the total content of 5′-GMP and 5′-IMP was 0.16. A weight% enzyme-treated tea extract (Invention 61) was prepared.

(Invention 62)
The inventive product 53 described in Example 12 and the comparative product 28 were mixed in a weight ratio (inventive product 1: comparative product 5 = 4: 1), and the total content of 5′-GMP and 5′-IMP was 0.21. A weight percent tea extract (Invention 62) was prepared.
Table 19 shows the composition of the tea extracts of Comparative Products 28 and 35 and Invention Products 60 to 62.

(Sensory evaluation test 7)
Test Example 7: Sensory evaluation of the green tea extract shown in Table 19 [Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
The prepared various tea extracts were dissolved in ion-exchanged water so that the concentration of tea polyphenol was 60 mg / 100 mL, respectively, and then comparative product 28 and comparative product 35, comparative product 28 and inventive product 60, comparative product 28 and inventive product 61, comparison Each combination of product 28 and invention product 62 was tested for umami and bitter and astringent taste by a two-point comparison method (two-point identification method), and the stronger one and the lower bitterness and taste were selected. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The results are shown in Table 20.

Results of sensory evaluation test (Table 20), comparative product 28 and invention product 53 were mixed to adjust the total content of 5′-GMP and 5′-IMP (comparative product 35, invention products 60 to 62) Compared with the comparative product 28, it was found that the umami was stronger. Regarding the bitter astringency, the tea extract (comparative product 35) having a total content of 5'-GMP and 5'-IMP in the tea extract solid content of 0.08% is not significantly different from the comparative product 28 in terms of bitter astringency. It was. On the other hand, the tea extract (invention products 60 to 62) in which the total content of 5′-GMP and 5′-IMP in the tea extract solids is 0.1% or more is significantly bitter compared to the comparative product 28. It was confirmed that the taste was lowered. From these facts, it was found that the total content of 5′-GMP and 5′-IMP in the tea extract with enhanced umami and reduced astringency needs to be 0.1% or more.

(Invention 63)
75 g of commercially available green tea leaves were extracted with 1500 g of a 0.15% aqueous sodium hydrogen carbonate solution (pH 8.3) at 90 ° C. for 60 minutes. After solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. 0.1N hydrochloric acid was added to this green tea extract to adjust to pH 5.5, and then concentrated with an evaporator and freeze-dried to obtain a green tea extract. 10 g of the obtained green tea extract was dissolved in 1000 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 300 mg of nuclease “Amano” G (manufactured by Amano Enzyme) (21 units for 100 mg of tea solids) and 300 mg of deamizyme G (manufactured by Amano Enzyme) were used. 150,000 units) per 100 mg were added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated green tea extract (Invention 63).

(Invention 64)
Invention 64 was prepared by carrying out the same treatment as Invention 63, except that the solution during tea leaf extraction was changed to a 0.15% aqueous potassium carbonate solution (pH 11.2).

(Invention 65)
Invention 65 was prepared by carrying out the same treatment as Invention 63, except that the solution at the time of tea leaf extraction was changed to a 0.02 M aqueous sodium hydroxide solution (pH 12.4).

(Comparative product 36)
75 g of green tea leaves were extracted with 1500 g of 0.02 M hydrochloric acid (pH 1.5) at 90 ° C. for 60 minutes. After solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. A saturated aqueous sodium hydrogen carbonate solution was added to the extract to adjust to pH 5.5, and then concentrated with an evaporator and freeze-dried to obtain a green tea extract. 3 g of the obtained green tea extract was dissolved in 300 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 90 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (21 units for 100 mg of tea solid content) and 90 mg of deamizyme G (manufactured by Amano Enzyme Co., Ltd.) 150,000 units) per 100 mg were added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and dried with a freeze dryer to obtain an enzyme-treated tea extract (Comparative Product 36).

(Comparative product 37)
A comparative product 37 was prepared by carrying out the same treatment as the comparative product 36 except that the solution at the time of tea leaf extraction was changed to a 0.15% citric acid solution (pH 2.7).
The component compositions of Comparative Products 36 and 37 and Invention Products 53 and 63 to 65 are shown in Table 21 and FIG.

As shown in Table 21 and FIG. 6, the pH of the extraction solution was adjusted to be alkaline (pH 8.3 to 12.4) using sodium hydrogen carbonate, potassium carbonate, or sodium hydroxide, which can be used for food processing. When extracted with water, the total content of 5′-GMP and 5′-IMP in the tea extract solids is 1.9 to 2.5 times higher than when extracted with water, and the taste is stronger and bitter and astringent. It was found that an enzyme-treated tea extract with reduced sucrose could be prepared. On the other hand, when extracted with water whose pH is adjusted to acidic (pH 1.5 to 2.7) using hydrochloric acid or citric acid that can be used for food processing, it is extracted with tea compared to when extracted with water. The total content of 5′-GMP and 5′-IMP in the solid content is reduced to 1/6 or less, and no umami enhancement or bitterness / astringency reduction effects are found even when compared with the enzyme-untreated product. It was not possible to prepare an enzyme-treated tea extract.

Preparation of enzyme-treated tea extract with reduced tea polyphenol content (Comparative product 38, Invention product 66)
Invention product 65, 2.5 g was dissolved in 250 g of ultrapure water to prepare a 1% solution. This solution was applied to a column (220 mL) packed with Diaion HP-20 (Mitsubishi Chemical Corporation) resin equilibrated with water and eluted with water (700 mL) to obtain a non-adsorbed HP-20 fraction. . Thereafter, the HP-20 non-adsorbed fraction was concentrated by an evaporator and then freeze-dried to obtain 1.7 g of an enzyme-treated tea extract (Invention 66) having a reduced polyphenol content. Next, methanol was further passed through the Diaion HP-20 column to obtain an HP-20 adsorption fraction. The HP-20 adsorbed fraction was concentrated with an evaporator and then freeze-dried to obtain 0.8 g of HP-20 adsorbed tea extract (Comparative product 38). Table 22 shows the component analysis results of these tea extracts.

The results of component analysis are shown in Table 22. The tea extract obtained by treating the inventive product 65 with Diaion HP-20 to reduce the tea polyphenol content in the solid content of the enzyme-treated tea extract (Inventive product 66). Could get.

Reduction of tea polyphenols by activated carbon (Comparative products 39-43, Invention products 67-71)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm, pH 8.2) containing sodium bicarbonate and sodium ascorbate. After solid-liquid separation, the mixture was filtered using a filter paper (No. 28, manufactured by Advantech Co., Ltd.), adjusted to pH 5.0 by adding 0.1N hydrochloric acid to obtain a green tea extract.
(1) 500 mL of the obtained green tea extract was heated to 50 ° C., and then nuclease “Amano” G (Amano Enzyme, Inc., 720 mg (5040 units)) and Deamizyme G (Amano Enzyme, Inc.) 720 mg (36000000 units) After incubating for 30 minutes, the enzyme reaction was stopped by heating in boiling water for 3 minutes.The obtained enzyme reaction solutions were subjected to the following treatments (A) to (E).
(A) 100 mL of the enzyme reaction solution was concentrated as it was with an evaporator and then freeze-dried to obtain an enzyme-treated tea extract (Invention 67).
(B) 100 mL was processed at 40 ° C. for 30 minutes using 1.45 g of activated carbon (0.60 times the amount of tea extract solids). After removing the activated carbon, the obtained solution was concentrated with an evaporator and freeze-dried to obtain an enzyme-treated tea extract (Invention 68).
(C) 100 mL of the enzyme-treated tea extract (invention product) was treated in the same manner as in (B) except that the amount of activated carbon was changed to 2.16 g (0.90 times the solid content of the tea extract). 69). (D) 100 mL of the enzyme-treated tea extract (invention product) was treated in the same manner as (B) except that the amount of activated carbon was changed to 2.90 g (1.20 times the amount of tea extract solids). 70). (E) 100 mL of the enzyme-treated tea extract (Invention 71) was processed in the same manner as (B) except that the amount of activated carbon was changed to 3.63 g (1.51 times the solid content of the tea extract). )
(2) 500 mL of another green tea extract was subjected to the following treatments (i) to (v). (I) 100 mL was concentrated by an evaporator as it was and then freeze-dried to obtain a tea extract (Comparative Product 39).
(Ii) 100 mL of activated carbon 1.44 g (0.63 times the amount of tea extract solids) was added and stirred at room temperature for 40 minutes, and then the activated carbon was removed by filtration to obtain an activated carbon treatment solution. After heating this activated carbon treatment solution to 50 ° C., 23.7 mg (166 units) of nuclease “Amano” G (manufactured by Amano Enzyme) and 23.7 mg (1185000 units) of deamizyme G (manufactured by Amano Enzyme) were added. After incubating for 30 minutes, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated tea extract (Comparative Product 40).
(Iii) 100 mL includes 2.14 g of activated carbon (0.93 times the amount of tea extract solids) and 20.7 mg (144.9 units) of nuclease “Amano” G (manufactured by Amano Enzyme) and deamizyme A comparative product 41 was obtained by carrying out the same treatment as in (ii) except that the amount of G (manufactured by Amano Enzyme Co., Ltd.) was changed to 20.7 mg (1035,000 units).
(Iv) 100 mL has an activated carbon amount of 2.75 g (1.2 times the amount of tea extract solids) and an nuclease “Amano” G (Amano Enzyme Co., Ltd.) amount of 15.5 mg (108.5 units). ) And Deamizyme G (Amano Enzyme Co., Ltd.) were used in the same manner as (ii) except that the amount was changed to 15.5 mg (775000 units), and Comparative Product 42 was obtained.
(V) 100 mL has an activated carbon amount of 3.2 g (1.4 times the amount of tea extract solids) and a nuclease “Amano” G (Amano Enzyme Co., Ltd.) amount of 12.5 mg (87.5 units). ) And Deamizyme G (manufactured by Amano Enzyme Co., Ltd.) were changed to 12.5 mg (625,000 units), and the same treatment as in (ii) was performed to obtain a comparative product 43. The component analysis results of these tea extracts are shown in Table 23.

As shown in Table 23, when the tea polyphenol is reduced by the activated carbon treatment in the enzyme-treated tea extract production process, the activated carbon treatment is performed after the 5′-phosphodiesterase and 5′-adenylate deaminase treatment, whereby the enzyme-treated tea extraction is performed. It was found that an enzyme-treated tea extract with reduced tea polyphenol content in the solid content of the product was obtained.

Enzyme reaction temperature (Invention 72-76)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm) containing sodium bicarbonate and sodium ascorbate. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. The obtained green tea extract was subjected to the following treatments (A) to (E).
(A) 200 mL of the above green tea extract was heated to 25 ° C., and then nuclease “Amano” G (Amano Enzyme) 200 mg (1400 units) and Deamizyme G (Amano Enzyme) 200 mg (10000000 units) were added. The reaction was started by adding. After reacting for 30 minutes, the reaction was stopped by heating in boiling water for 3 minutes, concentrated by an evaporator, and freeze-dried to obtain an enzyme-treated tea extract (Invention 72).
(B) 200 mL of the enzyme-treated tea extract (Invention 73) was obtained by performing the same treatment as (A) except that the temperature of the enzyme reaction was changed to 35 ° C.
(C) 200 mL of the enzyme-treated tea extract (Invention 74) was obtained by performing the same treatment except that the temperature of the enzyme reaction was changed to 50 ° C.
(D) 200 mL of the enzyme-treated tea extract (Invention 75) was obtained by performing the same treatment as (A) except that the temperature of the enzyme reaction was changed to 60 ° C.
(E) 200 mL of the enzyme-treated tea extract (Invention 76) was obtained by performing the same treatment as (A) except that the temperature of the enzyme reaction was changed to 70 ° C. The component composition of these tea extracts is shown in Table 24.

Table 24 and FIG. 7 show the results of the enzyme reaction with the enzyme amount, reaction time, and pH being constant and the enzyme reaction temperature was changed to 25 to 70 ° C. As a result, the target enzyme-treated tea extract could be obtained at any reaction temperature of 25 to 70 ° C., but the amount of 5′-IMP produced was small at 60 ° C. and 70 ° C. It was found that adenylate deaminase activity was significantly reduced.

Enzyme reaction pH
(Comparative products 44-45, invention products 77-81)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm) containing sodium bicarbonate and sodium ascorbate. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. The obtained green tea extract was subjected to the following treatments (A) to (G).
(A) 200 mL of the above green tea extract was adjusted to pH 3.0 by adding 0.1N hydrochloric acid, heated to 50 ° C., and 200 mg (1400 units) of nuclease “Amano” G (Amano Enzyme Co., Ltd.) and deamizyme 200 mg (10000000 units) of G (Amano Enzyme Co., Ltd.) was added to initiate the reaction. After the reaction for 30 minutes, the reaction was stopped by heating in boiling water for 3 minutes, concentrated by an evaporator, and freeze-dried to obtain an enzyme-treated tea extract (Comparative product 44).
(B) 200 mL of the enzyme-treated tea extract was subjected to the same treatment as (A) except that the pH of the enzyme reaction was changed to 4.0 (pH adjustment: using 0.1N hydrochloric acid) (Invention 77) Got.
(C) 200 mL of enzyme-treated tea extract was subjected to the same treatment as (A) except that the pH of the enzyme reaction was changed to 4.5 (pH adjustment: using 0.1N hydrochloric acid) (Invention 78) Got.
(D) 200 mL of the enzyme-treated tea extract (Invention 79) was subjected to the same treatment as (A) except that the pH of the enzyme reaction was changed to 5.0 (pH adjustment: using 0.1N hydrochloric acid). )
(E) 200 mL of the enzyme-treated tea extract (Invention 80) was subjected to the same treatment as (A) except that the pH of the enzyme reaction was changed to 5.5 (pH adjustment: using 0.1 N hydrochloric acid). Got.
(F) 200 mL of the enzyme-treated tea extract (Invention 81) was treated in the same manner as (A) except that the pH of the enzyme reaction was changed to 6.0 (pH adjustment: using sodium bicarbonate). Obtained.
(G) 200 mL of the enzyme-treated tea extract (Comparative Product 45) was treated in the same manner as (A) except that the pH of the enzyme reaction was changed to 7.0 (pH adjustment: using sodium bicarbonate). Obtained. The component composition of these tea extracts is shown in Table 25.

  Table 25 and FIG. 8 show the results of 5′-phosphodiesterase and 5′-adenylate deaminase reactions performed at a constant pH of 3.0 to 7.0 with the enzyme reaction time, enzyme amount, and enzyme reaction temperature being constant. It was. As a result, at pH 3.0 and pH 7.0, the formation of 5′-GMP and 5′-IMP was not confirmed, and between pH 4.0 and 6.0, 5′-GMP and 5 ′ It was possible to prepare an enzyme-treated tea extract with a total content of '-IMP exceeding 0.1%.

Examination of enzyme amount (Invention products 82-86)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm) containing sodium bicarbonate and sodium ascorbate. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. 0.1N hydrochloric acid was added to the obtained green tea extract to adjust to pH 5.0, concentrated with an evaporator, and freeze-dried to obtain a tea extract. 21.3 g of the obtained tea extract was dissolved in 1000 mL of ultrapure water, and then the following treatments (A) to (E) were performed. (A) After 200 mL was heated to 50 ° C., 42.6 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) and 7amids of deamizyme G (manufactured by Amano Enzyme Co., Ltd.) 21.3 mg (25000 units for 100 mg of tea solids) was added and reacted for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to obtain an enzyme-treated tea extract (Invention 82). (B) 200 mL of the enzyme-treated tea was extracted by performing the same treatment as (A) except that deamizyme G (manufactured by Amano Enzyme Co., Ltd.) was changed to 42.6 mg (50000 units for 100 mg of tea solids). A product (Invention 83) was obtained. (C) 200 mL is the same as (A) except that Deamizyme G (Amano Enzyme Co., Ltd.) is changed to 127.8 mg (150,000 units with respect to 100 mg of tea solids). A product (Invention 84) was obtained. (D) 200 mL of the enzyme-treated tea extract (A) was treated in the same manner as in (A) except that Deamizyme G (manufactured by Amano Enzyme Co., Ltd.) was changed to 213 mg (250,000 units for 100 mg of tea solids). Inventive product 85) was obtained. (E) Enzyme-treated tea extract (200 mL) was treated in the same manner as (A) except that Deamizyme G (Amano Enzyme Co., Ltd.) was changed to 426 mg (500,000 units for 100 mg of tea solids). Inventive product 86) was obtained. The component composition of these tea extracts is shown in Table 26.

  Table 26 shows the results when the amount of 5'-phosphodiesterase was constant and the amount of 5'-adenylate deaminase was changed. As a result, it was found that the target enzyme-treated tea extract can be prepared with any combination of enzyme amounts. As for the amount of 5'-adenylate deaminase, the amount of 5'-IMP produced was maximized when 3 to 5% by weight was added to 100 mg of tea solids.

Examination of enzyme reaction time (Invention products 87-92)
100 g of commercially available green tea leaves were extracted for 60 minutes with 2000 g of ultrapure water (sodium bicarbonate 0.15%, sodium ascorbate 300 ppm) containing sodium bicarbonate and sodium ascorbate. After the solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a green tea extract. 0.1N hydrochloric acid was added to the obtained green tea extract to adjust to pH 5.0, and then concentrated with an evaporator and lyophilized to obtain a tea extract. 21.3 g of the obtained tea extract was dissolved in 1000 mL of ultrapure water and heated to 50 ° C., and nuclease “Amano” G (manufactured by Amano Enzyme) 213 mg (7 units with respect to 100 mg of tea solids) 213 mg of Deamizyme G (manufactured by Amano Enzyme Co., Ltd.) (50,000 units per 100 mg of tea solid content) was added to initiate the reaction. Sampling at 0 min, 30 min, 60 min, 90 min, 120 min and 150 min after the start of the reaction, heating in boiling water for 3 min, stopping the reaction, concentrating with an evaporator, freeze-drying, enzyme-treated tea extract (Invention products 87 to 92) were obtained.

  The amount of 5′-phosphodiesterase and 5′-adenylate deaminase with respect to 100 mg of tea extracted solids was kept constant, and the total content of 5′-GMP and 5′-IMP when the enzyme reaction was conducted up to 150 minutes was examined. The results are shown in Table 27 and FIG. As a result, the target enzyme-treated tea extract could be prepared with an enzyme reaction time of 15 minutes or longer.

Preparation of oolong tea extract (Comparative product 46, Invention product 93)
75 g of Oolong tea leaves were extracted with 1500 g of water at 90 ° C. for 60 minutes. After solid-liquid separation, filtration was performed using filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain Oolong tea extract. After concentration with an evaporator, the extract was freeze-dried to prepare Oolong tea extract (Comparative product 46). 1 g of the prepared oolong tea extract (Comparative product 46) was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 10 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (7 units for 100 mg of tea solid content) and 10 mg of deamizyme G (manufactured by Amano Enzyme Co., Ltd.) (tea solid content) 50000 units / 100 mg) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to prepare an enzyme-treated oolong tea extract (Invention 93). The component compositions of Comparative Product 46 and Invention Product 93 are shown in Table 28.

(Comparative product 47, Invention product 94)
75 g of Oolong tea leaves were extracted with 1500 g of 0.15% sodium hydrogen carbonate solution (pH 8.3) for 60 minutes. After solid-liquid separation, filtration was performed using filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain Oolong tea extract. After concentration with an evaporator, freeze drying was performed to prepare Oolong tea extract (Comparative Product 47). 1 g of the prepared oolong tea extract (Comparative product 47) was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 10 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (7 units for 100 mg of tea solid content) and 10 mg of deamizyme G (manufactured by Amano Enzyme Co., Ltd.) (tea solid content) 50000 units / 100 mg) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and freeze-dried to obtain an enzyme-treated oolong tea extract (Invention 94). The component compositions of Comparative Product 47 and Invention Product 94 are shown in Table 28.

(Sensory evaluation test 8)
Test Example 8: Sensory evaluation of the extract shown in Table 28 [Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
Each prepared tea extract is dissolved in ion-exchanged water so as to have a drinking concentration (polyphenol concentration of 60 mg / 100 mL), and then the comparative product 46 and the inventive product 93, and the comparative product 47 and the inventive product 94 are each combined with umami. The bitter and astringent tastes were tested by a two-point comparison method (two-point identification method), and the stronger one and the lower bitterness and taste were selected. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The results are shown in Table 29.

  As a result of the sensory evaluation test (Table 29), the oolong tea extract treated with 5′-phosphodiesterase (nuclease) and 5′-adenylate deaminase (deaminase) has a strong taste and bitterness compared to the control enzyme-untreated product. It turns out that it is falling.

Preparation of black tea extract (Comparative product 48, Invention product 95)
75 g of tea leaves were extracted with 1500 g of water at 90 ° C. for 60 minutes. After solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a black tea extract. It concentrated with the evaporator and freeze-dried and the black tea extract (comparative product 48) was obtained. 1 g of the prepared black tea extract (Comparative product 48) was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 10 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (7 units for 100 mg of tea solid content) and 10 mg of deamizyme G (manufactured by Amano Enzyme Co., Ltd.) (tea solid content) 50000 units / 100 mg) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to prepare an enzyme-treated black tea extract (Invention 95). The results of component analysis are shown in Table 30.

(Comparative product 49, Invention product 96)
75 g of tea leaves were extracted with 1500 g of 0.15% sodium hydrogen carbonate solution (pH 8.3) for 60 minutes. After solid-liquid separation, filtration was performed using filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain a tea leaf extract. After concentration with an evaporator, the extract was freeze-dried to prepare a black tea extract (Comparative Product 49). 1 g of the prepared black tea extract (Comparative product 49) was dissolved in 100 g of ultrapure water to prepare a 1% solution. After warming this solution to 50 ° C., 10 mg of nuclease “Amano” G (manufactured by Amano Enzyme Co., Ltd.) (7 units for 100 mg of tea solid content) and 10 mg of deamizyme G (manufactured by Amano Enzyme Co., Ltd.) (tea solid content) 50000 units / 100 mg) was added and incubated for 30 minutes. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and freeze-dried to obtain an enzyme-treated black tea extract (Invention 96). Table 30 shows the component analysis results of the comparative product 49 and the invention product 96.

(Sensory evaluation test 9)
Test Example 9: Comparison of untreated and non-enzyme-treated black tea leaf extract products The sensory evaluation was performed on the extracts shown in Table 30.
[Test method]
A sensory evaluation was conducted using 7 randomly selected men and women as panelists.
Each of the prepared tea extracts was dissolved in ion-exchanged water so as to have a drinking concentration (tea polyphenol concentration of 60 mg / 100 mL), and then each combination of Comparative Product 48 and Invention Product 95, Comparative Product 49 and Invention Product 96, The umami and bitter and astringent tastes were tested by a two-point comparison method (two-point identification method), and the stronger one and the lower bitterness and taste were selected. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The results are shown in Table 31.

  As a result of the sensory test shown in Table 31, even with black tea extract, the extract treated with 5'-phosphodiesterase and 5'-adenylate deaminase has stronger umami and reduced bitterness and astringency compared with the untreated extract. I found out.

Comparative example

Comparative Examples 1-4
The green tea leaves used in preparing the invention product 1 were pulverized to prepare tea leaves having a 20 mesh pass component of 60.4%. As shown in Table 32 below, nuclease “Amano” G (150 mg), deamizyme G (150 mg) or a mixture thereof (nuclease “Amano” G 150 mg and deamizyme G 150 mg) was added to 10 g of this ground tea leaf. Thereafter, 20 g of ion-exchanged water was added and mixed well. The container containing the tea leaves was wrapped to prevent water evaporation and left at 35 ° C. for 12 hours. Next, the treated tea leaves were heated in an oven at 100 ° C. for 20 minutes to inactivate the enzyme and sterilized at the same time to obtain processed tea leaves. The processed tea leaves were placed in 300 mL of hot water at 75 ° C. and extracted for 4 minutes with occasional stirring. After this was subjected to solid-liquid separation, the obtained extract was concentrated with an evaporator and freeze-dried to obtain processed tea leaf extracts (Comparative Examples 1 to 4).

  Tea extract extracted using enzyme-treated tea leaves that have been subjected to enzyme treatment by adding 5′-phosphodiesterase, 5′-adenylate deaminase and a mixture of 5′-phosphodiesterase and 5′-adenylate deaminase directly to green tea leaves Then, it was found that the total content of 5′-GMP and 5′-IMP in the tea extract is small, and the desired tea extract cannot be obtained.

Preparation of Containerized Tea Beverage 50 g of commercially available green tea leaves were added to 1.5 L of water heated to 70 ° C., extracted for 4 minutes with stirring, and tea leaves were separated with a 100 mesh strainer. Subsequently, clarification was performed by filtration using filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain 1775 mL of an extract. Next, ion exchange water was added to 1000 mL of the extract to prepare a beverage raw material solution having a tea polyphenol concentration of 80 mg / 100 mL. The obtained beverage raw material liquid was subjected to the following treatments (A) to (C). (A) Sodium ascorbate was added to 600 mL of the beverage raw material solution so as to be 0.03% by weight, and then adjusted to pH 6.3 with sodium bicarbonate. The can was hot-packed into a can under a temperature condition of 80 ° C. or higher, and sterilized with a retort at 121 ° C. for 10 minutes to prepare a green tea beverage 1. (B) Inventive product 66 is added to 300 mL of beverage raw material solution to 5 ppm, 10 ppm, 25 ppm, 50 ppm, 100 ppm, 250 ppm, 500 ppm, and 1000 ppm, respectively, so that sodium ascorbate is 0.03% by weight. Added. Then, after adjusting to pH 6.3 with sodium hydrogencarbonate, the can was hot-packed into a can under temperature conditions of 80 ° C. or higher, and sterilized with retort at 121 ° C. for 10 minutes to prepare green tea beverages 2-9. (C) Green tea beverages 10 and 11 were prepared in the same manner as (B) after adding Invention Product 11 to 50 ppm and 1000 ppm with respect to 300 mL of beverage raw material liquid. Table 33 shows the component analysis results of the green tea beverage prepared above.

(Sensory evaluation test 10)
Test Example 10: Sensory evaluation of the extract shown in Table 33 Sensory evaluation was performed using 7 randomly selected men and women as panelists.
Using the green tea beverages shown in Table 32, the green tea beverages 2 to 11 were tested with respect to the umami and bitter taste by the two-point comparison method (two-point identification method) with the green tea beverage 1 using the green tea beverage 1 as a control. The stronger one and the lower bitter taste were selected. Judgment was made based on the probability of binomial distribution, and the significance level was 20%. The evaluation ○ in Table 33 is significantly different from that of the green tea beverage 1, and × is not significant.

  The results of the sensory evaluation test are shown in Table 33. In the beverage to which Invention Product 11 was added, the beverage in which Invention Product 11 was added in an amount of 50 ppm or more confirmed the effect of enhancing umami and the effect of reducing bitterness and astringency. On the other hand, in the beverage to which the invention product 66 was added in an amount of 10 ppm or more, the umami enhancing effect and the bitter and astringent taste reducing effect could be confirmed, but the addition of 5 ppm could not confirm the umami enhancing effect and the bitter and astringent taste reducing effect.

Preparation of Instant Powdered Tea Each component in the mixing ratio shown in Table 34 using black tea extract (MN-10: Mitsui Norin Co., Ltd .; tea polyphenol 27.3% by weight), sucrose, skim milk powder, creaming powder, and fragrance By mixing, powdered black tea 1 (instant milk tea powder) was prepared. Furthermore, the powdered black tea 2 (instant milk tea powder) which added the enzyme-treated black tea extract (invention 96) so that it might become 25 ppm addition with respect to the powdered black tea 1 was prepared. Moreover, the powdered black tea 3 (instant milk tea powder) which added the enzyme-processed black tea extract (invention 96) so that it might become 200 ppm addition with respect to the powdered black tea 1 was prepared. Furthermore, powdered tea 4 (instant milk tea powder) was prepared by adding the enzyme-treated black tea extract (Invention 96) so that 1000 ppm was added at a drinking concentration to powdered tea 1. These compounding amounts are shown in Table 34.

(Sensory evaluation test 11)
Test Example 11: Sensory evaluation of the extracts shown in Table 34 Sensory evaluation was performed using 7 randomly selected men and women as panelists.
Each 15.0 g of powdered black tea with the formulation shown in Table 34 was dissolved in 140 mL of hot water. Using the black tea 1 as a control, the taste and bitter astringency of the black tea 2, 3 and 4 were tested by a two-point comparison method (two-point identification method). One with stronger taste and lower bitterness than control was selected. Judgment was made based on the probability of binomial distribution, the significance level was 20%, no significant difference compared to powdered black tea 1, and there was significant difference.

  The results of the sensory evaluation test are shown in Table 34. Powdered teas 2 to 4 prepared by adding the enzyme-treated black tea extract (Invention 96) had significantly enhanced umami and reduced bitterness compared to the powdered beverage 1.

Reduced bitterness and enhanced umami of enzyme-treated tea extract for grapefruit juice (a) Enzyme-treated green tea extract (Invention 1) was added to commercially available grapefruit juice (Kirin Tropicana 100% Juice Grapefruit: manufactured by Kirin Tropicana) Two types were prepared: 0.02 wt% (200 ppm) added and well stirred, (b) 0.02 wt% (200 ppm) of enzyme-treated green tea extract (Invention 53) added and stirred well. .

(Sensory evaluation test 12)
Test Example 12: Sensory evaluation of the beverage prepared in [0146] Sensory evaluation was performed using 7 randomly selected men and women as panelists.
The grapefruit juice prepared in [0146] was used for the test.
The taste and bitterness of the sample to which invention product 1 was added and the product to which invention product 53 was added were tested by a two-point comparison method (two-point identification method), with the control without using the enzyme-treated green tea extract. One with stronger taste and lower bitterness than control was selected. Judgment was made based on the probability of binomial distribution, the significance level was 20%, no significant difference compared to the control, and x significant.

  The results of the sensory evaluation test are shown in Table 35. Grapefruit beverages with the addition of the enzyme-treated green tea extract (Invention 1) and the enzyme-treated green tea extract (Invention 53) have significantly enhanced umami and reduced bitterness compared to the additive-free product (Control). did.

Bitterness reduction and umami enhancement confirmation test of enzyme-treated tea extract for sports drink Example of reducing bitterness and umami enhancement effect by enzyme-treated tea extract using commercially available sports drink (Helsia Water: manufactured by Kao Corporation) It investigated like 25. The results are shown in Table 36.

  The results of the sensory evaluation test are shown in Table 36. Sports drinks with the addition of the enzyme-treated green tea extract (Invention 1) and the enzyme-treated green tea extract (Invention 53) have significantly enhanced umami and reduced bitterness compared to the additive-free product (Control). did.

Bitterness reduction and umami enhancement confirmation test of enzyme-treated tea extract for carbonated drink Example of reducing bitterness and umami enhancement effect by enzyme-treated tea extract using commercially available carbonated drink (Helsia Sparkling: manufactured by Kao Corporation) It investigated like 25. The results are shown in Table 37.

The results of the sensory evaluation test are shown in Table 37. Carbonated beverages with the addition of the enzyme-treated green tea extract (Invention 1) and the enzyme-treated green tea extract (Invention 53) have significantly enhanced umami and reduced bitterness compared to the additive-free product (Control). did.

Bitter taste reduction and umami enhancement confirmation test of enzyme-treated tea extract for chocolate After heating and dissolving commercially available chocolate (chocolate effect cacao 95% Box: manufactured by Meiji Seika Co., Ltd.), (a) enzyme-treated green tea extract ( Invented product 1) 0.02 wt% (200 ppm) added and well stirred and cooled in refrigerator, (b) Enzyme-treated green tea extract (Invented product 53) added 0.02 wt% (200 ppm) Two types of well-stirred were prepared. The sensory evaluation test was performed in the same manner as in Example 25.

The results of the sensory evaluation test are shown in Table 38. The chocolate to which the enzyme-treated green tea extract (Invention product 1) and the enzyme-treated green tea extract (Invention product 53) were added had significantly enhanced umami and reduced bitterness and astringency compared to the additive-free product (Control). .

Using extraction residue as raw tea, nuclease and deaminase treated tea extract black tea extraction residue black tea leaf 50g was added to 1.5L of water heated to 80 ° C, and extracted for 4 minutes with stirring, Tea leaves were separated with a 100 mesh strainer to obtain 204 g of tea leaf extract residue and 1258 mL of black tea extract. The black tea extract was further clarified by filtration using filter paper (No. 28, manufactured by Advantech Co., Ltd.).
(1) A saturated aqueous sodium hydrogen carbonate solution is added to 1000 mL of this black tea extract, adjusted to pH 5.5, heated to 50 ° C., and 153 mg (1070 units) of nuclease “Amano” G (Amano Enzyme Co., Ltd.) and deamizyme 153 mg (7650000 units) of G (Amano Enzyme Co., Ltd.) was added and incubated for 2 hours. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and dried with a freeze dryer to obtain 12.2 g of an enzyme-treated black tea extract (Invention 97).
(2) 204 g of the obtained tea leaf extraction residue was put into 1 L of a 0.15% aqueous sodium bicarbonate solution (pH 8.3) heated to 90 ° C. and extracted for 60 minutes. After solid-liquid separation, filtration was performed using a filter paper (No. 28, manufactured by Advantech Co., Ltd.) to obtain 844 mL of a tea leaf residue extract. 0.1N hydrochloric acid was added to 500 mL of this tea leaf residue extract, adjusted to pH 5.5 and heated to 50 ° C., and 58 mg (406 units) of nuclease “Amano” G (Amano Enzyme Co., Ltd.) and Deamizyme G (Amano) Enzyme Co., Ltd. (58 mg, 2900000 units) was added and incubated for 2 hours. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated with an evaporator and then freeze-dried to obtain 4.3 g of an enzyme-treated tea leaf residue extract (Invention 98).
Table 39 shows the component analysis results of Inventions 97 and 98. From this result, it was found that tea extract containing 0.1% or more of 5′-GMP or 5′-IMP was obtained not only from tea leaves but also from tea leaf residues.

Reduction of tea polyphenol by PVPP 20 g of enzyme-treated black tea extract was prepared in the same manner as in Invention 96.
(1) After 5 g of the obtained enzyme-treated black tea extract was dissolved in 200 mL of ultrapure water, 2.5 g of PVPP (Daibagan F, manufactured by BASF) was added (0.5 times the amount of tea solids). And stirred at room temperature (25 ° C.) for 30 minutes. Thereafter, PVPP was removed by filtration using filter paper (No. 1, manufactured by Advantech Co., Ltd.). The filtrate was concentrated with an evaporator, freeze-dried, and 4.22 g of an enzyme-treated black tea extract (Invention 99) obtained by PVPP treatment was obtained.
(2) 3.62 g of enzyme-treated black tea extract (invention product 100) was obtained in the same manner as in (1) except that the amount of PVPP used was changed to 5 g (1 times the amount of tea solids).
(3) 3.34 g of enzyme-treated black tea extract (Invention product 101) was obtained in the same manner as (1) except that the amount of PVPP used was changed to 10 g (twice the amount of tea solids).
Table 40 shows the component analysis results of Invention Products 99, 100, and 101. From this result, when the tea polyphenol is reduced by PVPP treatment in the enzyme-treated tea extract production process, the solid content of the enzyme-treated tea extract is obtained by PVPP treatment after 5′-phosphodiesterase and 5′-adenylate deaminase treatment. It was found that an enzyme-treated tea extract with a reduced content of tea polyphenols was obtained while suppressing a decrease in the concentration of 5′-GMP and 5′-IMP therein.

Preparation of enzyme-treated instant powdered green tea and instant powdered black tea (1) After dissolving 5 g of commercially available instant powdered green tea (produced in India) in 200 mL of ultrapure water, sodium bicarbonate was added to adjust the pH to 5.5. Warmed to ° C. Nuclease “Amano” G (manufactured by Amano Enzyme) 50 mg (350 units) and Deamizyme G (manufactured by Amano Enzyme) 50 mg (2,500,000 units) were added and reacted for 2 hours. Next, the enzyme reaction was stopped by heating in boiling water for 3 minutes. This was concentrated by an evaporator and then freeze-dried to obtain enzyme-treated instant powder green tea (Invention 102).
(2) An enzyme-treated instant powdered black tea (Invention 103) was obtained in the same manner as (1) except that the instant powdered tea used was changed to a commercially available instant powdered black tea (produced in Kenya).
(3) After dissolving 5 g of commercially available instant powder black tea (produced in India) in 200 mL of ultrapure water, 0.1N hydrochloric acid was added to adjust the pH to 5.5. Thereafter, enzyme-treated instant powder black tea (Invention 104) was obtained in the same manner as in (1).
Table 41 shows the component analysis results of Invention Products 102, 103, and 104.
From these results, it was found that instant powder green tea and instant powder black tea containing 5′-GMP and 5′-IMP can be obtained from commercially available instant powder green tea and instant powder black tea by enzyme treatment.

The umami enhancement and bitterness / astringency reducing agent in the present invention is used for tea drinks, carbonated drinks, fruit juice drinks, vegetable drinks, soy milk drinks, coffee drinks, powdered drinks, concentrated drinks, sports drinks, nutrition drinks, alcoholic drinks, etc. can do.

Claims (6)

  Guanosine-5 in the solid content of the obtained enzyme-treated tea extract has a step of allowing an enzyme having 5′-phosphodiesterase activity to act on an extract obtained by extracting tea as a raw material with water or an aqueous solution. A method for producing an enzyme-treated tea extract, wherein the content of '-monophosphate (5'-GMP) is 0.1% by weight or more.   The obtained enzyme treatment comprises a step of allowing an enzyme having 5′-phosphodiesterase activity and an enzyme having 5′-adenylate deaminase activity to act on an extract obtained by extracting tea as a raw material with water or an aqueous solution. The total content of guanosine-5′-monophosphate (5′-GMP) and inosine-5′-monophosphate (5′-IMP) in the solid content of the tea extract is 0.1% by weight or more. A method for producing an enzyme-treated tea extract.   An enzyme-treated tea extract obtained by the production method according to claim 1 or 2. To claim 1 or 2 enzyme-treated tea extract obtained by the process according, obtained by adding the enzyme the untreated tea extract, guanosine-5'-monophosphate in solid content (5'-GMP) And inosine-5′-monophosphate (5′-IMP) in a total content of 0.1% by weight or more.   An umami enhancement and bitterness / astringency reduction agent for foods and drinks comprising the enzyme-treated tea extract according to claim 3 or 4 as an active ingredient.   A method for enhancing umami and reducing bitterness and taste of food and drink, characterized by adding the enzyme-treated tea extract according to claim 3 or 4.